Hidradenitis suppurativa and perianal Crohn disease: differential diagnosis.

The first description of perianal fistulas and complications in Crohn disease was made 75 years ago by Penner and Crohn. Published studies have subsequently confirmed that perianal fistulas are the most common manifestations of fistulising Crohn disease. Hidradenitis suppurativa was described in 1854 by a French surgeon, Aristide Verneuil. It is a chronic, inflammatory, recurrent and debilitating disease of the pilosebaceous follicle, that usually manifests after puberty with deep, painful and inflamed lesions in the areas of the body with apocrine glands, usually the axillary, inguinal and anogenital regions. The differential diagnosis between hidradenitis suppurativa and Crohn disease can be challenging, especially when the disease is primarily perianal. When they occur simultaneously, hidradenitis suppurativa and Crohn disease show severe phenotypes and patients can respond to anti-tumour necrosis factor therapy, although adalimumab is currently the only treatment with demonstrated efficacy in hidradenitis suppurativa and Crohn disease. In addition, there is sometimes a need for different complementary surgical procedures.